macook,
To designate who is to get Non-Delivery Reports (NDRs), use Exchange System Manager to set the desired Non Delivery Report recipient:
1. In ESM, navigate to Servers -> Protocols -> SMTP.
2. Right click Default SMTP Queue, select Properties.
3. Go to the Messages tab.
4. In the field titled Send Copy of Non-Delivery Report to:, enter a valid SMTP mail address. For example: postmaster@your_domain.tld

Microsoft recommends that you also create a postmaster e-mail address for NDRs that come from other servers. This can be a secondary SMTP address for a user or a mail-enabled user account. Use Active Directory Users and Computers to add the e-mail address or mail-enabled account.

To process infrequent NDR messages, this user will not initially receive the actual message that caused the NDR until the postmaster or administrator opens the NDR itself and clicks 'Send Again.' This in turn retrieves the original message that generated the NDR, and can be forwarded if desired.